Surge-voltage recorder



June 17, 1930'. c. M. FOUST 1,765,227

SURGE VOLTAGE RECORDER Filed Aug. 6, 1926 Fig].

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Patented June 17, 1930 UNITED srA'ras PATENT OFFICE ULII'I'OID I. IOUST, 'OI' SCHENIOTAIDY, NEW YORK, ASSIGNOB TO GENERAL ELECTRIC OOIPANY, A CORPORATION 01' NEW YORK I sums-venues nnconnna Application fled August a, 1920. Serial in. 127,110.

My invention relates to that class of apparatu's employed to record electrical phenomena by means of the so-called Lichtenberg fi res, which are most effectively produced y the ex ure of a photo-sensitive film to electricaf r lischarges. For a more complete description of the nature of such records, see the article Kl donograph by J Peters, Electrical orld, April 19, 1

Recording. apparatus of this class has been I used to determine the magnitude and character of electrical surges occurring on transmission systems. It is known that the fig- V ures produced by a positive surge or charge are larger and of-a different character than those produced by a negative surge of the same magnitude. When the ordinary Lichtenberg camera is connected to a transmission line the half cycleof positive polarity t erefore determines the size of the spot or gure formed on the hoto-sensitive film. Over-voltage surges 0 negative polarity will not appear until they are of such magnitude that they produce a negative figure larger than the positive line voltage. It.is desirable that all over.voltage surges be recorded regardless of their polarity and it is the primary object of my invention to provide recording apparatus for this purpose.

In carrying my invention into efiect, I rovide apparatus which records all surges h positive and negative so that they appear as positive res, yet so that those which are produ by a negative surge are identified as such. In carrying my invention into effect 'I prefer to connect two recorders in parallel, but with reversed polarity betwelefn hthe transmifssion line almd und. t e su e is 0 positive o arit; it will be reoord d by the records? connected in the positive direction to the transmission line, and if it is of negative larity it will be recorded by the recorder 0 reverse polarity which is connected in the positive direction to ground. When a positive figure is being produced byone recording element, the corresponding negative figure is also produced at the other recording element, so that large positive and negative figures produced by exactly the same surge may be compared. If the sur e is alternating in character, a positive gure will be produced by both recording elements simultaneously, but the positive and negative components of such a charge may be studied and compared directly by a comparison of the two positive figures.

Another feature of my invention which is applicable to recording apparatus generally is a novel way of photographing t1me characters directly upon the film.

The features of my invention whichare believed to be novel and patentable will be inted out in the claims appended hereto.

or a better understandin of my invention, reference is made in t e following description to the accompanying drawing in which Fig. l represents electrical connections for a preferred form of theapparatus; F i 2 shows a view, partially 1n section, 0 the recording apparatus; Fig. 3 represents a sectional view taken on line 33 of Fig. 2; Fi 4 represents the nature of the record produced b Fig. 5is a detail view of t e time recording element and Fig. 6 is an enlarged view of one of thetime records.

Referring to Fig. 1,10 re resents a section of a transmission line to w ich the apparatus of my invention is connected to record surges occurring on-said line. Any convenient connection may be employed to obtain a voltage for the recording ap aratus which is proportional to the line vo tage. In the present case I have shown the line connected to ground through a string of hi h tension insulators 11. This string of insu ators will function as a; condenser without allowing any appreciable flow of power between the line 10 and ound. The recording apparatus indicate at 12 is connected across a portion of this string and ground so that a voltage proportional to line voltage will be available for recording purposes. Preferably the connection will be made as near the apparatus; I

ground as possible, as at 13, so as to keep the cording the ed between point 13 and ground to more exactly calibrate the volta e impressed upon the recorder. The essential parts of the recorder here shown comprise a drum 15 of insulating material having two internal conductin cylinders or electrodes 16 and 17 insulate from each other. A photo-sensitive film or recordin element 18 is supported and moved'by the ruin on a portion of its exterior surface, and two bluntly pointed electrodes 19 and 20 rest lightly upon this film opposite to the two con ucting cylinders 16 and 17. Electrode 19 -is connected to the voltage tap 13 and the correspondin cylinder 16 is connected to ground, while e ctrode 20 is connected to ound and the corresponding cylinder 1% is connected to the voltage tap 13.. Thus the drum is divided into two sections, one section 19, 16 for resitive surges, and the other section 20, 1%. for recording the ne ative surges, both sections being arranged, ue to the reversed polarity,to record such sur es as positive figures. Similar electrical is char es simultaneously pass through the recording element in opposite directions. If it is desired that all voltage changes occurring on "the transmission line he recorded,

' the switch indicated at 21 is kept closed.

If it is desired to record only surges in excess of line voltage, the switch 21 is opened and the spark gap indicated at 22 is adjusted so that ordinary line voltages will not cause a discharge thereacross but so that voltages in excess of line voltages will.

The recording apparatus is preferably constructed in porta e form as indicated in Figs. 2 and 3. The drum is rotatabliy ed in a light tight box 25 and is riven by suitable clockwork or other timing motor indicated at 26 through appropriate gearing indicated at 27. The arts are electrically connected as shown in Fig. 1, the manner of mountmaking electrical connection to the rotating sections of the drum being indicated at 28. The photo-sensitive film is wound from a s 001 29 about the drum onto a s 01 30.

he driving connection for the spools 29 and '30 being provided by elastic bands 31 and 32 which are stretched over the drum and spools outside of the film, as more clearly shown in Fig. 3. The type of drive automatically takes care of the varying diameter of the I rolls 29 and 30. The film is kept tight by causing 'a slight friction on the shaft from which the film is unwound. An adjustable s ring pressed against the end of the spool sliaft, as indicated at 33, may be used for this pur se. The film ,is moved forward at a suita le ratesay one-half inch per hou rand the apparatus may contain enoughfilmand be otherwise arranged to operate a week, for example, without attention, recording such phenomena as occur on the transmission line to which it is connected. Preferabl a timing wheel indicated at 34 is connected with the drum shaft throu h a friction clutch 35 and the film is timed y exposing the underside of the film in alinement with the electrodes 19 and 20 to a light emitting element throughwindows in a timing drum 37 driven with, the timing wheel 34. The light ray emitting element shown at R in F1 5 may be a small amount of radium salt eld in place on the end of an arin indicated at 36. A small lamp might also. serve for this urpose. Pre erably, the time is photogra he on the film in the manner shown in 1g. 5. The holes 38 in the timing drum 37 are covered by a strip of transparent material such as tracing paper 39 forming windows, and over each hole the time character, indicated as A and 1,'is printed on the tracin paper in bronze ink or some other material t rou h which the rays do not readily pass. T e shadow of the character is photographed. When the film is developed, we have an outline or shadow of the figure which remained unex sed in a circular exposed, section of the fi' in, as indicated in-the enlarged section of the film in Fig. 6. The drum is preferably arranged to rotate once in 24 hours so that by providing twenty-four holes evenly s aced the hours are reproduced on the film.

or 12:00 a. in. and 12:00 p. m., instead of the numbers, I print the characters A and P on the tracing aper, thereb distingu shing the a. m. an p. m. recor s so that the a proximate time a surge record occurs is in icated directly.

When the film is developed the Lichtenberg figures indicative of the potential surges are of the character represented in Fig. 4. The left end of the record which has the continuous bands 40 indicative of the normal alternating current voltage of the line is produced with the switch 21, Fig. 1, closed. The right end of the record is produced by abnormal surges alone such as are large enough to jump the spark gap 22 with the switch 21 open. The upper record is produced by the positive electrode 19 and the lower record is produced by the ne tive electrode 20. Vertically alined recor s are roduced simultaneously by the same surge.

hus, figures 41 and 42 were produced by a positive surge of approximately 18 kilovolts; 41 is the positive figure and 42 the corresponding negative figure; 43 and 44 were produced by a negative surge of ap:

proximately 9 kilovolts; 45 and 46 is the not only that the magnitude of the surge. may be more accuratelv determined in accordance withthe calibration of the instrument, but in order that the occurrence of the surge may become known at all.

The apparatus Will be found useful for ineasurlng or indicating the occurrence of 'various electrical phenomenon and is not limited to the use hereinbefore described.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have ibunderstood that the apparatus shown and described is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is 1. Apparatus for recording figures indica tive of the polarity and magnitude of voltages comprising two similar recording devices each comprising a sensitive recording element and electrodes for passing an electric discharge through such element and parallel circuit connections associated with said electrodes for impressing voltages of equal magnitude but of opposite polarity upon said recording devices.

2. Recording apparatus comprising a drum of insulating material, a pair of cylindrical electrodes insulated from each other inside of the drum, a photo-sensitive record sheet supported on the exterior of said druin,

bluntly pointed electrodes resting lightly on the outer surface of said record sheet opposite to said cylindrical electrodes, and circuit connections for connecting said two sets of electrodes in parallel but in opposite directions across a source of voltage.

3. The method of recording voltages by means of positive and negative Lichtenberg figures which consists in separating the volt age charge into two equal parts, and producing positive Lichtenberg figures with one part and negative Licliten erg figures with the other part of said voltage charge.

In witness whereof I have hereunto set 'iny hand this 5th day of August, 1926.

CLIFFORD M. FOUST. 

